From 703b2ca94467a029942fa478a38f0a14c8109766 Mon Sep 17 00:00:00 2001 From: Bharat Bhushan Date: Fri, 1 Mar 2019 13:33:58 +0800 Subject: [PATCH] vfio/fsl-mc: Improve send mc-command and read response Actually there is no ordering need when reading response from mc-portal. Similarly when writing the mc-command, ordering needed before command is submitted. This patch removes un-necessary barriers, response is read relaxed and maintain ordering when submit command. This also fixes compilation issue with newer kernel. Signed-off-by: Bharat Bhushan Signed-off-by: Yangbo Lu --- drivers/vfio/fsl-mc/vfio_fsl_mc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c @@ -331,9 +331,7 @@ static int vfio_fsl_mc_dprc_wait_for_res u64 header; struct mc_cmd_header *resp_hdr; - __iormb(); - header = readq(ioaddr); - __iormb(); + header = cpu_to_le64(readq_relaxed(ioaddr)); resp_hdr = (struct mc_cmd_header *)&header; status = (enum mc_cmd_status)resp_hdr->status; @@ -353,9 +351,12 @@ static int vfio_fsl_mc_send_command(void { int i; - /* Write at command header in the end */ - for (i = 7; i >= 0; i--) - writeq(cmd_data[i], ioaddr + i * sizeof(uint64_t)); + /* Write at command parameter into portal */ + for (i = 7; i >= 1; i--) + writeq_relaxed(cmd_data[i], ioaddr + i * sizeof(uint64_t)); + + /* Write command header in the end */ + writeq(cmd_data[0], ioaddr); /* Wait for response before returning to user-space * This can be optimized in future to even prepare response